1. Technical Field
The disclosure relates to a device and method for controlling a frame, and more particularly to a device and method for controlling frame input and output.
2. Related Art
A display is used for displaying a frame. However, sometimes, the display encounters a situation in which an input frame rate and a supported output frame rate are different. For example, in a personal computer system, a frame rate sent in a display through a display card may be different from a display update frequency of the display (usually set to 60 Hz). When frame rates of the input frame and the output frame are different, frame rate conversion (FRC) must be performed.
In a conventional FRC method, a buffer is usually used for storing frame data temporarily, and the buffer may be divided into one frame buffer area or two frame buffer areas. For one frame buffer area, since input and output of the same frame buffer area are implemented at the same time, a previous frame or a next frame may easily affect a current frame when a rate difference between frame input in the frame buffer area and frame output from the frame buffer area is too large, that is, a so-called frame tear problem may easily occur. Here, the frame tear means that an upper and a lower part of an actually displayed frame are data belonging to different frames.
The other method is to divide one buffer into two frame buffer areas, so as to alleviate the frame tear problem. In this manner the two frame buffer areas are alternately accessed at a low frame rate, and the other frame buffer area is selected to be accessed at a high frame rate according to one frame buffer area being accessed at the low frame rate, thereby preventing the current frame from being affected when input and output of either frame buffer area are implemented at the same time.
Although the method of two frame buffer areas can alleviate the frame tear problem, the limited space of the buffer means that the same buffer being divided into two frame buffer areas results in a size of a supportable input or output frame being much smaller than that supportable in the case of merely one frame buffer area. That is to say, for buffers having the same capacity, frame quality supportable in the method of merely one frame buffer area is higher than that in the method of two frame buffer areas. Similarly, in order to achieve the same supportable frame quality, a buffer having a larger capacity is needed for the method of two frame buffer areas, thus causing costs to rise.